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AST 301:Final Study Guide
formation of the inner solar system
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accretion, heating, differentiation
formation of solid crust, heavy cratering, wide spread mare-like volcanismo, reduced volcanism, possible plate tectonics, mantle solidification, end of tectonic activity,cool interior, no activity
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planet surfaces are modified by
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meteor impacts and by escape heat from the inside
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how much heat escapes from planets depends on
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the size of the planet
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typical meteorites hit a planet at
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several tens of km/s
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large meteorites have enough energy to vaporize many times the
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mass of the rock
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the vaporized material expands with the force of a hydrogen bomb and leaves behind an
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impact crater
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true/false: in the early solar system, every body was bombarded by meteorites
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TRUE
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most traces of meteorites on earth have been ____ away by
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eroded, weathering
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the cratered highlands of Mars record the
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intensity of bombardment
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volcanism is (or was) common for
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Venus, Earth, and Mars
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large lava flows have ___ much of Venus in the past 500 million years
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resurfaced
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smaller, more steady flows of lava and ash build up ___ ___ such as Mauna Loa on Earth and Olympus Mons on Mars, such mountains are sometimes demolished by ___ ___
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volcanic mountains, explosive eruptions
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tectonic activity =
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continental drift
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the crust of the earth consists of right plates floating on
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partly molten rock
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driven by convection, the plates separate in ___ zones , slide past each other in ___ zones , and come together in ___ zones
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rift, fault, subduction
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the resulting earthquakes trace the outlines of the
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plates
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spreading apart at underwater rift zones, earth's ocean floor has been _____ in the last few 100 million years
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resurfaced
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the continents are ___ and more ___ than the ocean plates
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thicker, buoyant
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when continental plates collide, the rock is
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pushed up to form mountain ranges
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tectonic activity and volcanism are caused by
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escape of heat from the inside of a planet
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if the earth had no ___ ___, it would have cooled off a long time ago
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internal heat
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why is the earth still hot inside?
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radioactive heating
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radioactive rock gets warm because
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the decay of unstable atoms gives off energy
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the rock that makes up the earth is only slightly radioactive, but the energy released is
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enough to keep it hot inside
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true/false: radioactive isotopes of potassium, uranium, and thorium make most of the heat inside the earth
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true
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radioactive rocks are also present in other terrestrial planets, why?
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bigger planets have more radioactive stuff per unit of surface area, therefore a big planet like earth stays hotter inside and so is more geologically active than small planets like mars
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mars is made of
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rock, metal
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mars, interesting feature?
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evidence for abundant water long ago
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mars, northern plains are
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low, smooth
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mars, southern planes are
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high, and heavily cratered and old
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the Tharsis Bulge was produced by
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convection in the molten interior
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(Tharsis Bulge) the convection was not quite strong enough to break crustal plates and move them: on Mars, there is no evidence of
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continental drift
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On earth, continental plates move around pushed by convection in the
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molten interior
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__ giant shield volcanoes on Tharsis Bulge
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4
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the shield volcanoes on Tharsis Bulge grew huge because
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1. the hot spots didn't move
2.because the crust is thick enough and the gravity is low enough to support their weight
3. the lava flow rate was large
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olympus mons is similar to but much ___ than Mauna loa and Mauna Kea (Hawaii)
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bigger
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largest volcano in solar system is
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Olympus Mons on Mars
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what is Vallis Marineris?
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On Mars, rift+water-erosion canyon (bigger than grand canyon)
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liquid water was abundant on ____ and had a ___ atmosphere 1-3 billion years ago
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Mars, thicker
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catastrophic floods, the last flood happened ___ years ago, because of the collapse of a dam holding lake formed when the glaciers of the last ice age melted
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18,000
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what is the result of the catastrophic floods?
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"anastomosing patter" of enormous scale, with partly streamed islands separating the various branches
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a temporary green house effect on ____ , what is it? (controversial but fascinating theory)
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Mars, a variety of features on Mars may be explained by episodic ocean and ice-sheet formation. The formation of valley networks early in Mar's history is evidence for a hydrological cycle that may have involved a persistent ocean. Cataclysmic flooding triggered by Tharsis volcanism may have lead to repeated ocean formation and dissipation on the northern plains and associated glaciation in the southern highlands,
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there is evidence (on Mars) for recent flows of a small amount of water:
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we see fragile erosion features that can't last long
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if there is ice not far under the surface and especially if liquid water sometimes seeps out, then this improves the chance that
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life may survive now from earlier times when the climate was better
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layers near the North polar cap were caused by ____ ___ ___, not water
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seasonal dust storms
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Viking Program
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Landed on Mars
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Mars rovers "Spirit" and "Opportunity" are now ~3700 days (10.2 Earth years) into their 90-day mission. "Opportunity" is still working
"Opportunity" landed inside
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a small crater
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what is the importance of blueberries on Mars?
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Hermatite is an iron oxide that is frequently deposited in standing water.
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true/false: blueberries on Mars show that there was volcanoes
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false, they appear to have formed within the layers and because they do not show impact features
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spectra show that blueberries are
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hematite, all of this is further evidence for standing water on Mars in the distant past
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(Mars) digging into the dirt under the lander revealed
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white water ice
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mars red color is due to
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iron oxide
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what is the largest channel on mars called
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valles marineris
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in the past, mars atmosphere was ____ , water was ____ , and temp was ___ due to ___
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thicker, abundant, higher, green house effect
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venus is made of
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rock, metal
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venus atmosphere, interesting feature
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run away green house effect
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venus is completely covered by
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sulphuric acid clouds
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the atmospheres of venus and earth are similar at ___ altitudes, but venus gets very hot under its ___
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high, clouds
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the main green house gas is
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carbon dioxide
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holes is mars imply a network of
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underground caverns
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in the summer, equatorial regions emit methane gas, methane gas __ last on mars
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won't
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there is NO sign of continental drift on venus but there are
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shield volcanoes like Olympus Mons on Mars and Mauna Loa in Hawaii
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venus: there are two main continents and several smaller highland regions
pancakes are believed to be
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extrusions of viscous lava
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true/false: venus has the thickest atmosphere of any terrestrial planet, surface pressure is 90 earth atmospheres
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TRUE
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venus shows us what happens when a planet suffers a _____ greenhouse effect it is dangerous to add too much ___ to earth's atmosphere
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runaway, C02
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venus has a HOT surface temp, so sulfur, water, c02 have all baked out of rock and into the atmosphere
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TRUE
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most of venus atmosphere is ___ which is an excellent absorber of ___ light
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C02, infared, that's how the greenhouse effect runaway
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venus rotates
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backwards
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venus and mars are
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opposite extremes of planetary evolution away from conditions that support life
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mars is too __ in mass and too __ from the sun, it got too cold, lost its air and water to space, to the soil, and to permafrost
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low, far
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venus is a little ___ to the sun, it got too __, it baked too many gases out of the soil and into the atmosphere, producing a runaway gas effect
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close, hot
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